Mountain bikers who want to tough it out through the winter will come forward when the season starts and be fitter than those who stayed inside during the cold winter months. SIDI made the Diablo GTX for hard-core mountain bikers who are not afraid of the cold. The engineers at SIDI designed four layers of protection in the Diablo. The layer closest to your foot is soft, so you feel comfortable. The next layer insulates you from the cold. The third is a seamless inner Gore-Tex® bootie that’s waterproof and breathable. The tough exterior of the shoe is made of Lorica® which is soft and strong like a good leather, while it also repels water, dries quickly, is breathable and permeable to water vapor. This is the ideal material for an outer layer for a cycling shoe in a sport that faces the elements on every ride. In addition to the material, the upper closely hugs around the ankle so no mud or wetness seeps in. The sole is mountain bike competition quality and it has optional toe spikes depending on the type of ride you have for the day. The Diablo is slightly roomier, so you can slip on those heavy winter socks and still slip into your shoes. The four Velcro® straps are easy to tighten and loosen so you fit perfectly and comfortably into your winter mountain bike shoe.